The invention relates to an electrodynamic direct linear drive and to a method for the production of a coil system comprising a plurality of coaxially arranged and sequentially following drive coils of an electrodynamic direct linear drive.
Electrodynamic direct linear drives, which are as a rule termed linear motors, generally possess a coil system able to be excited with a switched exciting voltage and a magnet system which is able to be moved in relation to the coil system and comprises a plurality of axially sequentially placed permanent magnets. The magnet system is a component of an output drive part able to be moved in relation to the coil system in the longitudinal direction thereof. By exciting the coil system the magnet system, and with it the entire output drive part, may be caused to perform a linear movement.
The coil system, which possesses a plurality of coaxially sequentially following drive coils, has so far normally been mounted on a coil carrier has, which is normally manufactured of synthetic resin material and possesses winding chambers divided off from one another by partitions, into which the drive coils are wound. The coil system is then, together with the coil carrier mounted on a return circuit means rendering possible a magnetic return path for the magnet system.
In order to provide for maximum power and energy density, there should be only minimum air gaps within the coil system. The consequently resulting requirements as regards the winding operation during the production of the coil system are relatively exacting and have an disadvantageous effect on the costs of production.
One aim of the present invention is to provide an electrodynamic direct linear drive and also a coil system for such a direct linear drive, in the case of which a higher power density may be obtained.
In order to attain this object an electrodynamic direct linear drive is provided comprising a coil system having a plurality of coaxially sequentially following drive coils, which is adapted to be subjected to a switched exciting voltage, a magnet system comprising permanent magnets, said permanent magnets being arranged axially sequentially following each other, said permanent magnets being arranged inside the internal space or on the external periphery of the coil system, said magnet system being designed as a component of an output drive part able to be moved in relation to the coil system in the longitudinal direction thereof, and furthermore comprising a return circuit means provided on the opposite side of the magnet system and internally or externally on the coil system, axially adjacent drive coils of the coil system resting directly contacting each other free of intermediate gaps.
Accordingly there is a departure from the prior art to the extent that the partitions of a coil carrier used in it between adjacent drive coils of the coil system are dispensed with and the mutually adjacent drive coils are directly in contact with one another. The volume occupied in the prior art by the partitions may therefore be filled by the copper material of the drive coils, this meaning that there is a higher degree of copper filling and therefore a substantially higher energy density. A consequence of this densely packed coil arrangement is the possibility of producing higher output forces.
Advantageous further developments of the electrodynamic direct linear drive will appear from the dependent claims.
In the case of the direct linear drive in accordance with the invention it is possible for a coil carrier to be dispensed with. More particularly, it is possible for the coil system to contact the return circuit means directly or if anything with the interposition of only of a thin insulation Layer on the return circuit means so that in this case as well there are no substantial intermediate spaces.
On the basis of the design in accordance with the invention it is possible for different specific configurations to be evolved. It is for example possible to design the return circuit means in a annular form and to arrange the coil system within the return circuit means so that it is coaxially surrounded, by the return circuit means. Furthermore, there is the possibility of designing the return circuit means in the form of a rod and placing in the internal space delimited by the coil system so that it is coaxially surrounded by the coil system.
It is convenient for the coil system to comprise at least two, as for instance two or three, respectively continuously wired coil system parts, which respectively comprise several drive coils, arranged coaxially to each other, the drive coils of the coil system parts being arranged alternatingly in sequence. Between axially adjacent drive coils of a respective coil system part it is convenient for a spanning section to extend, which spans the axial intermediate space, of the coil wire of the respective coil system part. The latter extends at the same level as the external periphery of the respective coil system part and extends past the at least one drive coil, arranged in the intermediate space, of the at least one further coil system part adjacent to the external periphery.
Consequently it is possible to prevent the spanning section of the coil wire of a respective coil system part from running on the coil floor of adjacent drive coils of another coil system part, something which ensures the production of an ideal coil form in the case of all drive coils. The arrangement of the coil wire over adjacent drive coils of another coil system part is accordingly not of crucial importance and does not interfere with the winding or degree of filling of the adjacent drive coils.
The individual coil system parts preferably each constitute a respective self-supporting, dimensionally stable structure with mutually coaxial drive coils. The individual coil system parts may be shaped like a comb and plugged in a direction athwart their longitudinal axis into each other. The dimensional stability may be obtained by the use of so-called bonding enamel wire as a coil winding wire, the coil wire consisting of copper being surrounded by a layer, which melts under the action of heat with the result that adjacent wire sections are joined together by the fused layer composition.
The initially mentioned object is furthermore to be attained by a method for the production of a coil system, comprising a plurality of coaxially sequentially following drive coils, of an electrodynamic direct linear drive, at least two continuously wired coil system parts being separately manufactured from each other, which respectively comprise a plurality of drive coils arranged coaxially and with a clearance between them, between which, at the same level as the external periphery, a spanning or bridging section of the continuous coil wire extends with the result that there is a comb-like structure, such coil system parts with a comb-like structure being plugged into one another in a direction athwart their longitudinal extent so that all drive coils are arranged coaxially to each other and the bridging or spanning sections of the coil wire extend past the at least one drive coil inserted into the spanned intermediate space of at least one further coil system part on the external periphery.
Owing to this there is the possibility of separately manufacturing the coil system parts, the assembly thereof being simply performed by plugging the resulting comb-like structures of the coil system parts into each other in the longitudinal direction, the drive coils of the respective one coil system part fitting into the intermediate adjacent drive coils of the one or respectively other coil system part or coil system parts.
Handling becomes particularly simple, if the individual coil system parts are baked after winding so that self-supporting, demensionally stable structure are produced.
The winding of the coil system parts is preferably implemented using a winding tool, which comprises axially spaced winding chambers resembling annular grooves, into which the coil wire for the production of the drive coils is wound.
The winding chambers are preferably, in the case of the winding tool employed, provided on a tool casing which comprises a plurality of casing segments, which are placed on the external periphery of an elongated tool core with a spacing from each other, and which may be shifted radially inward into the internal space of the coil system part to xe2x80x9cdemoldxe2x80x9d the coil system part produced, after the tool has been previously removed.